This project used cultured rat olfactory receptor cells to elucidate mechanism(s) of olfactory transduction and/or adaptation. These cells respond to a variety of odorants with rapid, dose-dependent, transient increases in intracellular cAMP. The first goal is to determine what classes of odorants change levels of cAMP, measured by radioimmunoassay, and to study the regulation of adenylate cyclase and phosphodiesterase activities during exposure to these odorants. The second goal is to determine if the same, or possibly other, classes of odorants regulate phsophoinositide turnover by comparison of PI and IP pools in radiolabelled cultures. Two-dimensional gel chromatography will be used to identify any proteins that are potentially phosphorylated upon odor stimulation. The third goal is to investigate the role of odorant binding protein in olfaction by determining the effect of OBP on the dose-response curves of odorant-induced changes in cAMP. These experiments will use recombinant rat OBP. A final series of experiments will determine if co-culturing primary olfactory receptor neurons with olfactory bulb alters the ability of odors to induct changes in levels of cAMP and, potentially, PI turnover and protein phosphorylation.